Comparison of sintering performance of typical specular hematite ores with distinct size distributions

The sintering performance of three typical specular hematite ores (coarse SO-A, intermediate SO-B and ultrafine SO-C) was compared in an industrial ore blend through pilot-scale sinter pot tests. The effect of particle size of specular hematite ores on their granulation and sintering performance was revealed. Compared with the coarse SO-A fine and ultrafine SO-C concentrate, the intermediate SO-B showed inferior granulation and sintering performance characterized with poorer bed permeability and productivity, lower sinter strength and higher fuel rates. A new material preparation method was hence proposed and verified at both pilot and industrial scales. The proposed method by mixing SO-B with a high amount of goethite-type iron ore fines was found to be an effective way in improving the granulation and assimilative characteristics of ore blend comprising 31% intermediate SO-B, leading to improved sinter productivity and lowered fuel rates. The metallurgical properties and microstructure of sinters were also investigated. The sinters obtained through the proposed preparation method were generally stronger and more reducible on account of better sinter structure with more relict hematite ultimately connected with needle-like silico-ferrite of calcium and aluminum and lower porosity.